Removal of Cl(-I) from strongly acidic wastewater containing Cu(II) by complexation-precipitation using thiourea: Efficiency enhancement by ascorbic acid
Removal of Cl(-I) from strongly acidic wastewater containing Cu(II) by complexation-precipitation using thiourea: Efficiency enhancement by ascorbic acid
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DOI：
10.1016/j.jhazmat.2020.123836
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发表时间：
2021-01-15
影响因子：
13.6
通讯作者：
Wang, Xianliang
中科院分区：
文献类型：
--
作者：
Guo, Panpan;Kong, Linghao;Wang, Xianliang
铜冶炼工业产生的强酸性废水含有高浓度的Cl（-I）、Cu（II）和H2SO 4。处理这类废水的常用方法是中和，这会产生大量的固体废物。为了避免产生固体废物，建议选择性地去除污染物，然后将废水作为稀硫酸再循环。提出了一种在抗坏血酸（AC）促进下硫脲（TU）络合沉淀法有效去除Cl（-I）的新方法。考察了影响Cl（-I）去除率的主要因素，并探讨了AC强化Cl（-I）去除的机理。结果表明，TU/AC/Cl（-I）摩尔比为1：3：1时，Cl（-I）去除率达到87.4%，残留Cl（-I）浓度从1000 mg/L降低到126.4 mg/L。机理研究表明，AC首先将Cu（II）还原为Cu（I），然后生成的Cu（I）迅速与TU络合形成[Cu（I）（x）（TU）（y）]（x+），最后[Cu（I）（x）（TU）（y）]（x+）与Cl（-I）以[Cu（I）（x）（TU）（y）]Cl-x形式沉淀。本研究为强条件下Cl（-I）的络合-沉淀提供了理论依据，为强酸性废水中Cl（-I）的去除提供了一种有效的方法。
Strongly acidic wastewater produced by copper smelting industries contains high concentrations of Cl(-I), Cu(II) and H2SO4. The common method for the treatment of this type of wastewater is neutralization, which produces large amounts of solid waste. To avoid the production of solid waste, it was proposed to selectively remove contaminants and then recycle the wastewater as diluted sulfuric acid. This study proposed a new complexation-precipitation method to effectively remove Cl(-I) using thiourea (TU) under the promotion of ascorbic acid (AC). The Cl(-I) removal efficiency was optimized, important effecting factors were investigated and the mechanisms of the AC-improved removal of Cl(-I) were studied. The results showed that, Cl(-I) removal efficiency reached 87.4 % under a TU/AC/Cl(-I) mole ratio of 1:3:1 and the residual Cl(-I) concentration was lowered from 1000 mg/L to 126.4 mg/L. The mechanism investigation showed that, AC first reduces Cu(II) to Cu(I), then, the produced Cu(I) is quickly complexed by TU to form the [Cu(I)(x)(TU)(y)](x+); finally, [Cu(I)(x)(TU)(y)](x+) precipitates with Cl(-I) in the form of [Cu(I)(x)(TU)(y)]Cl-x. This study provided a theoretical foundation of complexation-precipitation of Cl(-I) under strongly conditions and developed an effective method for removal of Cl(-I) from strongly acid waster.